Posts Tagged Brain–machine interface

Neuromuscular electrical stimulation (NMES), specifically functional electrical stimulation (FES) that compensates for voluntary motion, and therapeutic electrical stimulation (TES) aimed at muscle strengthening and recovery from paralysis are widely used in stroke rehabilitation. The electrical stimulation of muscle contraction should be synchronized with intended motion to restore paralysis. Therefore, NMES devices, which monitor electromyogram (EMG) or electroencephalogram (EEG) changes with motor intention and use them as a trigger, have been developed. Devices that modify the current intensity of NMES, based on EMG or EEG, have also been proposed. Given the diversity in devices and stimulation methods of NMES, the aim of the current review was to introduce some commercial FES and TES devices and application methods, which depend on the condition of the patient with stroke, including the degree of paralysis.

This paper reviews the current state of the art in robotic-aided hand physiotherapy for post-stroke rehabilitation, including the use of brain machine interfaces (BMI). The main focus is on the technical speciﬁcations required for these devices to achieve their goals. From the literature reviewed, it is clear that these rehabilitation devices can increase the functionality of the human hand post-stroke. However, there are still several challenges to be overcome before they can be fully deployed. Further clinical trials are needed to ensure that substantial improvement can be made in limb functionality for stroke survivors, particularly as part of a programme of frequent at-home high-intensity training over an extended period.

This review serves the purpose of providing valuable insights into robotics rehabilitation techniques in particular for those that could explore the synergy between BMI and the novel area of soft robotics.

Introduction

Strokes are a global issue aﬀecting people of all ethnicities, genders and ages [1]; approximately 20 million people per year worldwide suﬀer a stroke [2, 3]. Five million of those patients remain severely handicapped and dependent on assistance in daily life [4]. Once a stroke has occurred the patient may be left with mild to severe disabilities, depending on the type and severity of the stroke. This paper will focus on the primary issues experienced which are the clawing of the hand and stiﬀening of the wrist. In recent years, several new forms of rehabilitation have been proposed using robot-aided therapy. This work reviews the current state-ofthe-art robotic devices and brain-machine interfaces (BMI) for post-stroke hand rehabilitation, analysing current challenges, highlighting the future potential and addressing any inherent ethical issues.[…]

This single volume brings together both theoretical developments in the field of motor control and their translation into such fields as movement disorders, motor rehabilitation, robotics, prosthetics, brain-machine interface, and skill learning. Motor control has established itself as an area of scientific research characterized by a multi-disciplinary approach. Its goal is to promote cooperation and mutual understanding among researchers addressing different aspects of the complex phenomenon of motor coordination. Topics covered include recent theoretical advances from various fields, the neurophysiology of complex natural movements, the equilibrium-point hypothesis, motor learning of skilled behaviors, the effects of age, brain injury, or systemic disorders such as Parkinson’s Disease, and brain-computer interfaces.

Abstract

Brain–computer interfaces (BCIs) use brain activity to control external devices, thereby enabling severely disabled patients to interact with the environment. A variety of invasive and noninvasive techniques for controlling BCIs have been explored, most notably EEG, and more recently, near-infrared spectroscopy. Assistive BCIs are designed to enable paralyzed patients to communicate or control external robotic devices, such as prosthetics; rehabilitative BCIs are designed to facilitate recovery of neural function. In this Review, we provide an overview of the development of BCIs and the current technology available before discussing experimental and clinical studies of BCIs. We first consider the use of BCIs for communication in patients who are paralyzed, particularly those with locked-in syndrome or complete locked-in syndrome as a result of amyotrophic lateral sclerosis. We then discuss the use of BCIs for motor rehabilitation after severe stroke and spinal cord injury. We also describe the possible neurophysiological and learning mechanisms that underlie the clinical efficacy of BCIs.

Carmena, J. M.et al. Learning to control a brain–machine interface for reaching and grasping by primates. PLoS Biol.1, e2 (2003).This paper provides the most advanced and detailed neurophysiological analysis of the neuronal mechanisms behind brain–computer interface control of complex movements.

Hochberg, L. R.et al. Reach and grasp by people with tetraplegia using a neurally controlled robotic arm. Nature485, 372–375 (2012).The first paper describing multidemensional movement control of an arm–hand robotic device using an implanted microelectrode array in the primary motor cortex of a paralyzed patient.

Since the first experimental demonstrations in rats9, monkeys10,11, and the subsequent clinical reports in humans12,13,14, brain-machine interfaces (BMIs) have emerged as potential options to restore mobility in patients who are severely paralyzed as a result of spinal cord injuries (SCIs) or neurodegenerative disorders15. However, to our knowledge, no study has suggested that long-term training associating BMI-based paradigms and physical training could trigger neurological recovery, particularly in patients clinically diagnosed as having a complete SCI. Yet, in 60–80% of these “complete” SCI patients, neurophysiological assessments16,17 and post-mortem anatomical18 studies have indicated the existence of a number of viable axons crossing the level of the SCI. This led some authors to refer to these patients as having a “discomplete” SCI17 and predict that these remaining axons could mediate some degree of neurological recovery.

For the past few years, our multidisciplinary team has been engaged in a project to implement a multi-stage neurorehabilitation protocol – the Walk Again Neurorehabilitation (WA-NR) – in chronic SCI patients. This protocol included the intensive employment of immersive virtual-reality environments, combining training on non-invasive brain-control of virtual avatar bodies with rich visual and tactile feedback, and the use of closed-loop BMI platforms in conjunction with lower limb robotic actuators, such as a commercially available robotic walker (Lokomat, Hocoma AG, Volketswil, Switzerland), and a brain-controlled robotic exoskeleton, custom-designed specifically for the execution of this project.

Originally, our central goal was to explore how much such a long-term BMI-based protocol could help SCI patients regain their ability to walk autonomously using our brain-controlled exoskeleton. Among other innovations, this device provides tactile feedback to subjects through the combination of multiple force-sensors, applied to key locations of the exoskeleton, such as the plantar surface of the feet, and a multi-channel haptic display, applied to the patient’s forearm skin surface.

Unexpectedly, at the end of the first 12 months of training with the WA-NR protocol, a comprehensive neurological examination revealed that all of our eight patients had experienced a significant clinical improvement in their ability to perceive somatic sensations and exert voluntary motor control in dermatomes located below the original SCI. EEG analysis revealed clear signs of cortical functional plasticity, at the level of the primary somatosensory and motor cortical areas, during the same period. These findings suggest, for the first time, that long-term exposure to BMI-based protocols enriched with tactile feedback and combined with robotic gait training may induce cortical and subcortical plasticity capable of triggering partial neurological recovery even in patients originally diagnosed with a chronic complete spinal cord injury.

Methods

Eight paraplegic patients, suffering from chronic (>1 year) spinal cord injury (SCI, seven complete and one incomplete, see Fig. 1A, Supplementary Methods Inclusion/exclusion Criteria), were followed by a multidisciplinary rehabilitation team, comprised of clinical staff, engineers, neuroscientists, and roboticists, during the 12 months of 2014. Our clinical protocol, which we named the Walk Again Neurorehabilitation (WA-NR), was approved by both a local ethics committee (Associação de Assistência à Criança Deficiente, Sao Paulo, Sao Paulo, Brazil #364.027) and the Brazilian federal government ethics committee (CONEP, CAAE: 13165913.1.0000.0085). All research activities were carried out in accordance with the guidelines and regulations of the Associação de Assistência à Criança Deficiente and CONEP. Each participant signed written informed consent before enrolling in the study. The central goal of this study was to investigate the clinical impact of the WA-NR, which consisted of the integration between traditional physical rehabilitation and the use of multiple brain-machine interface paradigms (BMI). This protocol included six components: (1) an immersive virtual reality environment in which a seated patient employed his/her brain activity, recorded via a 16-channel EEG, to control the movements of a human body avatar, while receiving visuo-tactile feedback; (2) identical interaction with the same virtual environment and BMI protocol while patients were upright, supported by a stand-in-table device; (3) training on a robotic body weight support (BWS) gait system on a treadmill (Lokomat, Hocoma AG, Switzerland); (4) training with a BWS gait system fixed on an overground track (ZeroG, Aretech LLC., Ashburn, VA); (5) training with a brain-controlled robotic BWS gait system on a treadmill; and (6) gait training with a brain-controlled, sensorized 12 degrees of freedom robotic exoskeleton (seeSupplementary Material).

(A) Cumulated number of hours and sessions for all patients over 12 months. We report cumulated hours for the following activities: classic physiotherapy activities (e.g. strengthening/stretching), gait-BMI-based neurorehabilitation, one-to-one consultations with a psychologist, periodic measurements for research purposes and routine medical monitoring (vital signs, etc.). (B) Neurorehabilitation training paradigm and corresponding cumulated number of hours for all patients: 1) Brain controlled 3D avatar with tactile feedback when patient is seated on a wheelchair or 2) in an orthostatic position on a stand-in-table, 3) Gait training using a robotic body weight support (BWS) system on a treadmill (LokomatPro, Hocoma), 4) Gait training using an overground BWS system (ZeroG, Aretech). 5–6) Brain controlled robotic gait training integrated with the sensory support of the tactile feedback at gait devices (BWS system on a treadmill or the exoskeleton). (C) Material used for the clinical sensory assessment of dermatomes in the trunk and lower limbs: to evaluate pain sensitivity, examiner used a pin-prick in random positions of the body segments. Nylon monofilaments applying forces ranging between 300 to 0.2 grams on the skin, were used to evaluate patients’ sensitivity for crude to fine touch. Dry cotton and alcohol swabs were used to assess respectively warm and cold sensation. Vibration test was done using a diapason on patients’ legs bone surface. Deep pressure was assessed with an adapted plicometer in every dermatome.

Abstract

Noninvasive brain–machine interfaces (BMIs) are typically associated with neuroprosthetic applications or communication aids developed to assist in daily life after loss of motor function, eg, in severe paralysis.

However, BMI technology has recently been found to be a powerful tool to promote neural plasticity facilitating motor recovery after brain damage, eg, due to stroke or trauma.

In such BMI paradigms, motor cortical output and input are simultaneously activated, for instance by translating motor cortical activity associated with the attempt to move the paralyzed fingers into actual exoskeleton-driven finger movements, resulting in contingent visual and somatosensory feedback.

Here, we describe the rationale and basic principles underlying such BMI motor rehabilitation paradigms and review recent studies that provide new insights into BMI-related neural plasticity and reorganization.

Current challenges in clinical implementation and the broader use of BMI technology in stroke neurorehabilitation are discussed.

Abstract

Noninvasive brain–machine interfaces (BMIs) are typically associated with neuroprosthetic applications or communication aids developed to assist in daily life after loss of motor function, eg, in severe paralysis. However, BMI technology has recently been found to be a powerful tool to promote neural plasticity facilitating motor recovery after brain damage, eg, due to stroke or trauma. In such BMI paradigms, motor cortical output and input are simultaneously activated, for instance by translating motor cortical activity associated with the attempt to move the paralyzed fingers into actual exoskeleton-driven finger movements, resulting in contingent visual and somatosensory feedback. Here, we describe the rationale and basic principles underlying such BMI motor rehabilitation paradigms and review recent studies that provide new insights into BMI-related neural plasticity and reorganization. Current challenges in clinical implementation and the broader use of BMI technology in stroke neurorehabilitation are discussed.

Abstract

Noninvasive brain–machine interfaces (BMIs) are typically associated with neuroprosthetic applications or communication aids developed to assist in daily life after loss of motor function, eg, in severe paralysis. However, BMI technology has recently been found to be a powerful tool to promote neural plasticity facilitating motor recovery after brain damage, eg, due to stroke or trauma. In such BMI paradigms, motor cortical output and input are simultaneously activated, for instance by translating motor cortical activity associated with the attempt to move the paralyzed fingers into actual exoskeleton-driven finger movements, resulting in contingent visual and somatosensory feedback. Here, we describe the rationale and basic principles underlying such BMI motor rehabilitation paradigms and review recent studies that provide new insights into BMI-related neural plasticity and reorganization. Current challenges in clinical implementation and the broader use of BMI technology in stroke neurorehabilitation are discussed.

March 20, 2016

Ever hope to walk again was too strong. In the year 2016, numerous clinical trials worldwide, involving new techniques are being developed. And high-tech equipment are entering rehabilitation centers for paraplegic patients recover upright.

Ever hope to walk again was too strong. In the year 2016, numerous clinical trials worldwide, involving new techniques are being developed. And high-tech equipment are entering rehabilitation centers for paraplegic patients recover upright.

Exoskeletons, brain-machine interface, stimulation of the spinal cord …, many promising avenues seem to open, not to mention the spectacular, cell therapy that has already begun to prove itself. A Polish firefighter 40 years was able to walk again a few months ago thanks to a revolutionary treatment based on olfactory cells … (read S. and A. No. 815, January 2015). Today, the patient “feels good and continues to recover functionally,” says her surgeon Pawel Tabakov, associate professor at the Medical University of Wroclaw (Poland). “We are in intense preparation for the next step. “Geoffrey Raisman, researcher at the Institute of Neurology at University College London (UCL) and co-author of this essay promises:” Further clinical trials will be conducted this year. ”
Walking again is possible

With new patients, but always the same ingenious procedure. Walking again is possible. This is already the case in mutual center of functional rehabilitation Kerpape in Ploemeur (Morbihan). This seaside center which deals, among others, the trauma of the spinal cord, invested two years ago in “exoskeletons”. This term originally booked the hard shell of arthropods, now refers to the external robotic devices that attach to the patient’s body to support them and enable them to move forward. The legs are inserted in two grooves provided engines ankles and knees, powered by batteries carried in a backpack. The paraplegic rises relying on crutches and advance the basin. This single pulse then instructs the robotic legs to make a step forward, then another. Two models are in operation in the center of Kerpape, one developed by the Israeli company ReWalk, the other by the American company Ekso Bionics. “We are not magicians, though tempers Philippe Labarthe, director of rehabilitation care. Do not give false hopes. Nonetheless, this mobility aid could develop in five to ten years out of rehabilitation centers. “The major obstacle is the cost (about € 80,000), unaffordable for most patients.” For now, the work of verticality offered by these exoskeletons used to re train the patient to the effort, work and improve his cardiac, respiratory and muscle strength, “added Philippe Labarthe.

The benefit of such an exercise e? As to remuscler and e? Avoid the conse? Quences of a permanent sitting position in a wheelchair (ULCE? Res, troubles me? Taboliques, oste? Oporose …). Still, the exoskeletons of assistance are not has? their infancy. The idea? S would indeed can happen to be? Skittles to gain freedom? movement, pro- ject which has attele? e the socie? you? franc? Wandercraft comfortable. But the date of the first test does not cease for the time e? Be rejected? Seen before 2017.

A new route bypassing the spinal cord

The idea pursued by lighthouse researchers would also give back to reach the “voluntary” walking paraplegic. Indeed, victims of spinal cord no longer have control of their lower limbs because the transmission between the brain and the lower body is interrupted. Recall that the role of the spinal cord is to route the information to the brain of the various parts of the body through the nerves, which carry actuators but also sensory information from the body. When the leads that form the spinal cord is severed or crushed, the nerve fibers in the spinal cord do not grow back, preventing electrical controls the brain to play their role and paralyzing a number of functions.

At the University of California at Irvine (USA), the team of Dr. Christine King and has just reached a crucial stage. She found a way to restore that link brain-legs’ round the problem “in some way. And reconnecting the commands of the brain directly to the muscles, bypassing the spinal cord through a brain-computer interface. To do this it was first necessary to check a key point: “People with spinal cord injury-they retain the neurological signal the walk? And if so, can they still use it to control their locomotion? “Was first interviewed Christine King. To answer, the team turned to virtual reality, this digital universe that replaces the physical reality in which to submerge. She asked Paraplegic subjects to control an avatar (virtual character) via electrical signals from the brain, recorded by an electrode headset (electroencephalogram, EEG). And the device worked! “Patients whose spinal cord was injured therefore retain this neurological signal,” says the researcher.

Algorithms for processing brain signals

The next step was for patients to take control, always through these brain signals, an exoskeleton. Supported by a harness suspended – for security reasons – a paraplegic equipped with an EEG headset to focus his mind on the controls “on” or “idle”. Algorithms have immediately treated the brain signals recorded before transmitting, by the computer, the robotic legs of the system. “This is the first demonstration to the world that a person whose spinal cord is injured can recover a guided stroll through the brain and again perform a directed walking task, “are then excited researchers.

An additional step was taken in 2015. Finished the exoskeleton! This time, the patient’s legs have been equipped with an electrical stimulation system placed on the femoral and peroneal nerves. Still hanging on his harness, the patient can again adjust his thinking brain signals controlling “on” or “idle”. But the order was this time directly transmitted by the computer, to the electrodes of electrical stimulation of the muscles. Thirty workouts and nineteen weeks later, the patient was able to travel a distance of three meters. Never seen ! Now, “we are trying to miniaturize the system and reduce the number of electrodes needed to record brain signals,” said Christine King. The system does not suit all patients. “They must have retained the use of their arms and trunk movements. Those with a weakness or paralysis in the arms, as quadriplegics, are not able to maintain an upright posture during electrical stimulation. ”

Walk again is not a priority elsewhere quadriplegics according to experts. Regaining control of arm and hand grip is especially more important. “This would greatly improve their quality of life because it is probably more important to be able to eat alone than walking,” comments Christine King. For the future, the dream researcher systems controlled by sensors implanted directly into the brain. The University of Melbourne (Australia) is in the process of grant. The first test of an exoskeleton control by an electrode inserted into a brain artery, called “stentrode” is indeed announced for 2017. Elsewhere at the Federal Polytechnic School of Lausanne (Switzerland), we are preparing for a another first: repair spinal cord, rather than overcome its deficiencies. The team of French researcher Gregoire Courtine has already caused a sensation in 2014 by showing that it was possible to walk again paralyzed rats by stimulating electrically and chemically part of the severed spinal cord. The “Courtine” method showed that the neural circuits that control the operation can thus be reactivated. The results of an experiment conducted in monkeys should be published shortly. And already looming the first trial in humans. Expected results in 2017 … impatiently.

Previous motor imagery studies can be re-interpreted using these four factors.

Abstract

Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of ‘embodied cognition’ and also as a basis for neuro-rehabilitation and brain–machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors:

motor control

explicitness,

sensory modalities

agency.

Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future.

Somatotopically arranged brain activity during mental rotation (MR) of hands and feet (Hanakawa et al., 2007). Activity greater for the foot MR than for the hand MR (green) is situated dorsal to activity greater for the hand MR than for the foot MR (red). This arrangement agrees with the motor somatotopy of the motor and somatosensory areas where the foot representations are situated dorsal to the hand representations. Primary motor cortex (M1), primary somatosensory cortex (S1), dorsal premotor cortex (PMd), supplementary motor cortex (SMA).